Add Openverse Fetch Script (Initial Implementation)

[Babi-B]

Fixes

• Fixes [Feature] Add Openverse as a Data Source #184 by @Babi-B

Description

This PR introduces a new fetch script for collecting licensed data from the Openverse API

Technical details

• Implements modular design; only the fetch phase has been implemented
• The implementation fetches a small dataset (images) from the Openverse API
• The fetch data is stored in data/2025Q4/1-fetch/openverse_fetch.csv

Tests

• Referenced existing code (github_fetch.py) for best practices

Checklist

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• I added or updated tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no
  visible errors.

Developer Certificate of Origin

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Developer Certificate of Origin

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[TimidRobot]

This is a great start!

[TimidRobot]

Good work, getting closer

[najuna-brian]

@TimidRobot,
Hello, this is a good example: @Babi-B used a raise, this raises a new exception, signaling that something went wrong and stopping further normal execution, instead of using return [] which I explained here.

[TimidRobot]

Nearly done!

[TimidRobot]

Just a few trivial changes and then this PR can be merged!

[TimidRobot]

Thank you for your work on this!